JPH0534077Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas leak alarm device that drives a gas cutoff valve in the event of a gas leak, and more particularly to a gas leak alarm device that prevents self-damage due to gas.

[Conventional technology]

A conventional gas leak alarm device is constructed as shown in FIG. In the figure, 1 is a gas alarm that detects a gas leak, 2 is a circuit breaker that drives a gas cutoff valve 3 based on the output of the gas alarm 1, and 4 is a power plug that supplies AC power to the gas alarm 1. be.

The gas alarm 1 includes a gas alarm main circuit 7 that detects gas leaks, a detection circuit 16, and an external output circuit 8 that receives outputs from the main circuit 7 and the detection circuit 16 and outputs a drive signal to the gas circuit breaker 2. and a backup power supply 9.

Further, a limit switch 17 is built into the power plug 4, and is activated when the power plug 4 is pulled out from the power outlet. Switching of the limit switch 17 is detected by the detection circuit 16. Also, for AC power, plug 4
It is supplied to the main circuit 7 via.

In such a configuration, when the power plug 4 is attached to an outlet and AC power is normally supplied to the gas alarm 1, the limit switch 17 inside the plug 4 does not operate, and the detection circuit 16 outputs a detection output. does not occur. In this state, the main circuit 7 constantly monitors the gas leakage state, and when a gas leak occurs, the main circuit 7 outputs a detection signal, drives the gas circuit breaker 2 through the external output circuit 8, and operates the gas cutoff valve. Block 3.

On the other hand, when the power plug 4 is disconnected from the outlet due to self-damage, the limit switch 17 is activated and turns on or off, this state is detected by the detection circuit 16, and the detection output is passed through the external output circuit 8 to the gas circuit breaker. Supply to 2. As a result, even when the power plug 4 is pulled out from the outlet, the gas circuit breaker 2 is driven and the gas shutoff valve 3 is shut off.

The backup power supply 9 is provided to compensate for the operation of the detection circuit 16, the external output circuit 8, and the main circuit 7 when the plug is pulled out when power is no longer supplied to the gas alarm 1 during a power outage. .

[Problem that the invention attempts to solve]

In the conventional device configured as described above,
If an extension cord such as a table tap is connected between the AC power source and the power plug 4, there is no limit switch installed at the connection between the extension cord and the AC power source to detect if the extension cord is pulled out. Such a condition cannot be detected when the AC power source and extension cord are unplugged.

Further, due to restrictions on the structure of the power outlet, the operation of the limit switch 20 may become uncertain depending on the shape of the outlet, and if the power plug 4 is not inserted into the outlet sufficiently, the limit switch 20 will be activated and the detection circuit 19 detects this and causes a malfunction.

[Means for solving problems]

The present invention has been developed in view of the conventional problems as described above, and as shown in FIG. A gas alarm 1 that is activated by inserting a power plug 4 into a power outlet 10 from which gas leaks is detected, and a gas circuit breaker 2 that drives a gas cutoff valve 3 by the output of the gas alarm 1. The gas alarm 2 includes an oscillation circuit 5 and a level detection circuit 6 for detecting the output level of the oscillation circuit, and the oscillation circuit 5 has an output that is connected to the power plug 4. The level detection circuit 6 detects the output level of the oscillation circuit 5 during a power outage and when the power plug 4 is pulled out from the power outlet 10, and the level is detected only when the plug 4 is pulled out from the power outlet 10. The gas circuit breaker 2 is configured to be driven by the detection output of the detection circuit 6.

[Effect]

In the above means, when the power plug 4 is attached to the power outlet 10 and AC power 15 is being supplied, the gas leak alarm 1 monitors gas leaks, and when a gas leak occurs, the gas circuit breaker 2 is activated. A detection signal is output and the gas cutoff valve 3 is cut off.

When the AC power supply 15 is out of power, the plug 4 and the outlet 10 are connected, so the oscillation signal of the oscillation circuit 5 is transmitted to the load 11 such as the pole transformer 13 or the electrical equipment 12 through the power plug 4 and the power outlet 10. The load 11 attenuates the output level of the oscillation signal.

On the other hand, when the power plug 4 is pulled out from the outlet 10, there is no attenuation in the output path of the oscillation circuit 5. Therefore, the level detection circuit 6 outputs a detection signal only when the plug is pulled out by detecting the difference in the output level of the oscillation circuit 5 between this power outage and when the plug is pulled out, and the gas circuit breaker 2 is driven by the detection signal. Then, the gas cutoff valve 3 is shut off.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, the same parts as in FIGS. 1 and 4 are denoted by the same reference numerals. Inside the gas alarm 1, a gas alarm main circuit 7 is supplied with power from a power plug, and its output is input to an external output circuit 8. Further, the output of the oscillation circuit 5 is led out to the power plug 4 through the output transformer T, and is also input to the level detection circuit 6, and the output of the detection circuit 6 is input to the external output circuit 8.

Further, the AC power supply 15 is supplied to the pole transformer 13 through the power outage switch 14, and its secondary voltage is supplied as a general household power supply (AC 100V or 200V). A household electric appliance 12 and a power outlet 10 are connected to this power source, and the electric appliance 12 and a pole transformer 13 act as a load 11 for the output of the oscillation circuit 5.

In such a configuration, in a steady state where power is supplied to the power plug 4, power is supplied to the gas alarm 1 through the plug 4, and the main circuit 7 monitors gas leakage. When a gas leak occurs, a detection signal is output from the main circuit 7, and is input to the gas circuit breaker 2 through the external output circuit 7 to drive it, thereby shutting off the gas shutoff valve 3.

At this time, the oscillation circuit 5 outputs an oscillation signal. Since the oscillation signal is supplied to a load 11 such as an electrical device 12 or a pole transformer 13 through the transformer T, plug 4, and outlet 10, the oscillation output level is attenuated by the load 11, and as shown in FIG.
The waveform is shown in .

Further, when the power outage switch 14 is turned off and a power outage occurs, the oscillation circuit 5 continues to output an oscillation signal by the backup power supply 9. This oscillation signal is attenuated because it is supplied to the load 11 through the transformer T, the plug 4, and the outlet 10 as in the steady state, and its waveform becomes as shown in Figure 3b, which is the same as in Figure 3a. output level.

On the other hand, when the power plug 4 is pulled out from the outlet 10, the oscillation signal of the oscillation circuit 5 driven by the pack-up power supply 9 is not supplied to the load 11, and therefore is not attenuated at all. Therefore, the output waveform becomes as shown in FIG. 3c, and the output level becomes higher than that during normal operation and during a power outage.

Therefore, the level detection circuit 6 detects the difference in the oscillation signal output level from the oscillation circuit 5 between the power outage and the plug removal to determine whether the power is out or the plug is removed. The detection circuit 6 outputs a detection signal only when the oscillation signal level increases when the plug is pulled out, and inputs it to the gas circuit breaker 2 through the external output circuit 7 to shut off the gas cutoff valve 3.

In addition, in the event of a power outage or when the plug is disconnected, the gas alarm 1
Although power is not supplied to each component from then on, power is supplied from the backup power supply 9 to each component to compensate for subsequent operation.

FIG. 4 shows a specific example of the configuration of the present invention. In the figure, an oscillation circuit 5 includes a crystal oscillation circuit including a crystal oscillator Xtal and a transistor Q ₁ , and its oscillation output is amplified by a common base type transistor Q ₂ and input to an output transformer T, and a level detection circuit 6
Enter. Level detection circuit 6 is a comparator
CP, and the output of the oscillation circuit 5 is a diode D ₁ ,
The signal is supplied to the inverting input of the comparator CP through a rectifying and smoothing circuit constituted by capacitors C ₁ and C ₂ and resistor R ₁ . Further, the slider of the variable resistor VR ₁ is connected to the normal rotation input, and the reference voltage set by the variable resistor VR ₁ is applied. The external output circuit 8 is a photocoupler consisting of a light emitting diode D _p and a phototransistor Q _p .
Both ends of _{the light emitting diode D p are} connected to the detection output of the main circuit 7, and the cathode is connected to the output of the comparator CP.
Also, the output of the phototransistor Q _p is the gas circuit breaker 2
supplied to In such a configuration, the crystal oscillation circuit of the oscillation circuit 5 is driven during normal operation and during power outage,
The oscillation output is input to the output transformer T through the transistor _Q2 , and the load 11 is input through the plug 4.
, so its output level is attenuated. The oscillation output is rectified by diode _D1 ,
The DC signal is smoothed by a resistor R ₁ and capacitors C ₁ and C ₂ and applied to the inverting input of the comparator CP. On the other hand, the position of the slider of the variable resistor VR ₁ is set so that the output of the comparator CP is at H level during steady state and during power outage. Therefore, in this state, if no gas leakage is detected from the main circuit 7, the light emitting diode D _p is off, and no signal is output from the phototransistor Q _p . Further, when a gas leak occurs, the cathode side of the light emitting diode D _p is brought into a LOW state from the main circuit 7, and the light emitting diode D emits light. When this emits light, the phototransistor Q _p turns on,
Gas circuit breaker 2 is driven.

Furthermore, when the plug is pulled out, the output of the oscillation circuit 5 is not attenuated, so the inverting input of the comparator CP rises above the reference voltage set by the variable resistor VR ₁ .
The output of comparator CP is inverted to L level.
Therefore, the light emitting diode D _p is turned on regardless of the output of the main circuit 7, the phototransistor Q _p is turned on, and the gas circuit breaker 2 is driven.

In addition, during a power outage or when the outlet is unplugged, power is supplied to each component from the backup power source.

〔effect〕

As described above, according to the present invention, even if the power plug and the power outlet are connected by an extension cord, the gas cutoff valve can be shut off when the plug is pulled out due to self-damage. Furthermore, it is possible to distinguish between a power outage and a time when the plug is removed, and the gas cutoff valve can be shut off only when the plug is removed, and gas leakage can be monitored as usual during a power outage.

Furthermore, the detection operation is not uncertain depending on the shape of the outlet, and pulling out of the plug can be detected reliably.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the principle of the gas alarm device according to the present invention, Fig. 2 is a diagram showing an embodiment of the invention, and Figs. 3 a to C show oscillation signal waveforms of the oscillation circuit in Fig. 2. 4 are circuit diagrams showing a specific example of the present invention, and FIG. 5 is a diagram showing a conventional gas alarm device. 1...Gas alarm, 2...Gas circuit breaker, 3...
Gas cutoff valve, 4...power plug, 5...oscillation circuit, 6...level detection circuit, 7...gas alarm main circuit, 8...external output circuit, 9...backup power supply, 10...power outlet , 11...Load,
12...Electrical equipment, 13...Pole transformer, 14
...Power outage switch, 15...AC power supply.

Claims (1)

[Scope of claim for utility model registration] Gas alarm that detects leakage of gas supplied by plugging the power plug into the power outlet of an AC power supply to which loads such as pole transformers and electrical equipment are connected in parallel. In the gas leak alarm device, the gas alarm includes an oscillation circuit and a level detection circuit that detects the output level of the oscillation circuit. The output of the oscillation circuit is led to the power plug, and the level detection circuit detects the output level of the oscillation circuit during a power outage and when the power plug is pulled out from the power outlet, and the output level of the oscillation circuit is led out to the power plug. A gas leak alarm device characterized in that the gas leak alarm device is configured to drive a gas circuit breaker by the detection output of the level detection circuit only when the device is unplugged from the power outlet.